2020-07-22 21:17:48 +00:00
|
|
|
|
# Garbage Collection
|
|
|
|
|
|
|
|
|
|
|
|
`nix-env` operations such as upgrades (`-u`) and uninstall (`-e`) never
|
|
|
|
|
|
actually delete packages from the system. All they do (as shown above)
|
|
|
|
|
|
is to create a new user environment that no longer contains symlinks to
|
|
|
|
|
|
the “deleted” packages.
|
|
|
|
|
|
|
|
|
|
|
|
Of course, since disk space is not infinite, unused packages should be
|
|
|
|
|
|
removed at some point. You can do this by running the Nix garbage
|
|
|
|
|
|
collector. It will remove from the Nix store any package not used
|
|
|
|
|
|
(directly or indirectly) by any generation of any profile.
|
|
|
|
|
|
|
|
|
|
|
|
Note however that as long as old generations reference a package, it
|
|
|
|
|
|
will not be deleted. After all, we wouldn’t be able to do a rollback
|
|
|
|
|
|
otherwise. So in order for garbage collection to be effective, you
|
|
|
|
|
|
should also delete (some) old generations. Of course, this should only
|
|
|
|
|
|
be done if you are certain that you will not need to roll back.
|
|
|
|
|
|
|
|
|
|
|
|
To delete all old (non-current) generations of your current profile:
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-env --delete-generations old
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
|
|
|
|
|
Instead of `old` you can also specify a list of generations, e.g.,
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-env --delete-generations 10 11 14
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
|
|
|
|
|
To delete all generations older than a specified number of days (except
|
|
|
|
|
|
the current generation), use the `d` suffix. For example,
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-env --delete-generations 14d
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
|
|
|
|
|
deletes all generations older than two weeks.
|
|
|
|
|
|
|
|
|
|
|
|
After removing appropriate old generations you can run the garbage
|
|
|
|
|
|
collector as follows:
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-store --gc
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
2021-11-14 03:28:20 +00:00
|
|
|
|
The behaviour of the garbage collector is affected by the
|
2020-07-22 21:17:48 +00:00
|
|
|
|
`keep-derivations` (default: true) and `keep-outputs` (default: false)
|
|
|
|
|
|
options in the Nix configuration file. The defaults will ensure that all
|
|
|
|
|
|
derivations that are build-time dependencies of garbage collector roots
|
|
|
|
|
|
will be kept and that all output paths that are runtime dependencies
|
|
|
|
|
|
will be kept as well. All other derivations or paths will be collected.
|
|
|
|
|
|
(This is usually what you want, but while you are developing it may make
|
|
|
|
|
|
sense to keep outputs to ensure that rebuild times are quick.) If you
|
|
|
|
|
|
are feeling uncertain, you can also first view what files would be
|
|
|
|
|
|
deleted:
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-store --gc --print-dead
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
|
|
|
|
|
Likewise, the option `--print-live` will show the paths that *won’t* be
|
|
|
|
|
|
deleted.
|
|
|
|
|
|
|
|
|
|
|
|
There is also a convenient little utility `nix-collect-garbage`, which
|
|
|
|
|
|
when invoked with the `-d` (`--delete-old`) switch deletes all old
|
|
|
|
|
|
generations of all profiles in `/nix/var/nix/profiles`. So
|
|
|
|
|
|
|
2020-07-31 13:43:25 +00:00
|
|
|
|
```console
|
|
|
|
|
|
$ nix-collect-garbage -d
|
|
|
|
|
|
```
|
2020-07-22 21:17:48 +00:00
|
|
|
|
|
|
|
|
|
|
is a quick and easy way to clean up your system.
|
